Method of nuclear reprogramming

Abstract

This invention provides a method of producing an induced pluripotent stem cell comprising the step of introducing at least one kind of non-viral expression vector (more preferably a plasmid vector) incorporating at least one gene that encodes a reprogramming factor into a somatic cell. An induced pluripotent stem cell wherein no exogenous genes induced is integrated into the cellular genome is also provided.

1 . A method of producing an induced pluripotent stem cell, comprising the step of introducing at least one kind of non-viral expression vector incorporating at least one gene that encodes a reprogramming factor into a somatic cell. 
     
     
         2 . The method of  claim 1 , wherein the vector is a non-viral expression vector autonomously replicable outside a chromosome. 
     
     
         3 . The method of  claim 1 , wherein the vector is a plasmid vector. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the gene that encodes a reprogramming factor is one or more kind of genes selected from the group consisting of an Oct family gene, a Klf family gene, a Sox family gene, a Myc family gene, a Lin family gene, and the Nanog gene. 
     
     
         6 . The method of  claim 1 , wherein the gene that encodes a reprogramming factor is one of the following combinations:
 (a) a combination of two kinds of genes consisting of an Oct family gene and a Sox family gene;   (b) a combination of three kinds of genes consisting of an Oct family gene, a Klf family gene, and a Sox family gene;   (c) a combination of four kinds of genes consisting of an Oct family gene, a Klf family gene, a Sox family gene, and a Myc family gene;   (d) a combination of four kinds of genes consisting of an Oct family gene, a Sox family gene, a Lin family gene, and the Nanog gene; and   (e) a combination of six kinds of genes consisting of an Oct family gene, a Sox family gene, a Klf family gene, a Myc family gene, a Lin family gene, and the Nanog gene, or any one of these combinations further comprising the TERT gene and/or the SV40 Large T antigen gene.   
     
     
         7 . The method of  claim 1 , wherein the gene that encodes a reprogramming factor is one of the following combinations:
 (a) a combination of two kinds of genes consisting of Oct3/4 and Sox2;   (b) a combination of three kinds of genes consisting of Oct3/4, Klf4, and Sox2;   (c) a combination of four kinds of genes consisting of Oct3/4, Klf4, Sox2, and c-Myc;   (d) a combination of four kinds of genes consisting of Oct3/4, Sox2, Lin28, and Nanog; and   (e) a combination of six kinds of genes consisting of Oct3/4, Sox2, Klf4, c-Myc, Lin28, and Nanog,   or any one of these combinations further comprising the TERT gene and/or the SV40 Large T antigen gene.   
     
     
         8 . The method of  claim 1 , wherein the number of kinds of non-viral expression vectors introduced into the somatic cell is 1, 2, 3, or 4. 
     
     
         9 . The method of  claim 8 , wherein the gene that encodes a reprogramming factor is a combination of three kinds of genes consisting of an Oct family gene, a Klf family gene, and a Sox family gene, or a combination of four kinds of genes consisting of an Oct family gene, a Klf family gene, a Sox family gene, and a Myc family gene, wherein the Oct family gene, the Klf family gene, and the Sox family gene are incorporated in one kind of non-viral expression vector. 
     
     
         10 . The method of  claim 9 , wherein the Oct family gene, the Klf family gene, and the Sox family gene are incorporated in one kind of non-viral expression vector in this order in the orientation from the 5′ to 3′ end. 
     
     
         11 . The method of  claim 9 , wherein the Oct family gene, the Klf family gene, and the Sox family gene are incorporated in one kind of non-viral expression vector with an intervening sequence enabling polycistronic expression. 
     
     
         12 . The method of  claim 9 , wherein the Oct family gene is Oct3/4, the Klf family gene is Klf4, the Sox family gene is Sox2, and the Myc family gene is c-Myc. 
     
     
         13 . The method of  claim 9 , wherein a first non-viral expression vector and a second non-viral expression vector are concurrently introduced into a somatic cell. 
     
     
         14 . The method of  claim 13 , wherein said introduction is repeatedly performed twice or more. 
     
     
         15 . The method of  claim 1 , wherein the somatic cell is a somatic cell of a mammal, including a human. 
     
     
         16 . An induced pluripotent stem cell that can be obtained by the method of  claim 1 . 
     
     
         17 . The induced pluripotent stem cell of  claim 16 , wherein whole or part of the at least one non-viral expression vector introduced is substantially not integrated in the chromosome. 
     
     
         18 . A non-viral expression vector incorporating a gene that encodes at least one reprogramming factor. 
     
     
         19 . The vector of  claim 18 , wherein the vector is a plasmid vector. 
     
     
         20 . The vector of  claim 18 , wherein an Oct family gene, a Klf family gene, and a Sox family gene are incorporated. 
     
     
         21 . The vector of  claim 20 , wherein the Oct family gene, the Klf family gene, and the Sox family gene are incorporated in this order in the orientation from the 5′ to 3′ end. 
     
     
         22 . The vector of  claim 21 , wherein the Oct family gene, the Klf family gene, and the Sox family gene are incorporated via a sequence enabling polycistronic expression. 
     
     
         23 . The vector of  claim 20 , wherein the Oct family gene is Oct3/4, the Klf family gene is Klf4, and the Sox family gene is Sox2. 
     
     
         24 . An induced pluripotent stem cell wherein one or more transgenes encoding reprogramming factor are integrated into the cellular genome in the form of plasmid. 
     
     
         25 . An induced pluripotent stem cell wherein no exogenous genes introduced is integrated into the cellular genome. 
     
     
         26 . The vector of  claim 18 , harboring genes encoding two or more kinds of reprogramming factors, wherein the genes are incorporated via 2A sequence derived from foot-and-mouth disease virus.